This is a bonus cache for Adventure Lab 4 or 5 Bridges.
There is nothing hidden at these coordinates.
To find the cache, you need to complete the Adventure Lab and note the bonus numbers in the Journals.
The Adventure Lab app can be downloaded from the usual online suppliers and played on a smartphone.
The cache can be found at
N51 45.ABC. W1 16.DEF
Congratulations to Rabbithen for FTF on this and the Adlabs.
